Ganged potentiometer



Feb. 27, 1951 R. w. SEARLE GANGED POTENTIOMETER Filed Feb. 14, 1949 l/nwzd Z 156m m ted Feb. 21, 1,951

GANGED POTENTIOMETER Raymond W. Searle, Waltham, Masa, assignor to Technology Instrument Corporation, Waltham,

Application February 14, 1949, Serial No. 76,339

scams. 1

The present invention relates to ganged precision adjustable resistors or potentiometer-s, and more particularly a provision whereby such gang resistors or potentlometers may be synchronized The several potentiometers are retained together by a plurality of clamping rings I which engage the adjacent grooves Ill and 20 of the casings II.

As is apparent from Fig. 3 each of the rings I5 or adjusted relative to the unitary control knob 5 is formed of an upper portion I6 and a lower poror shaft. tion I1 retained together by a plurality of cap In certain control and measurement circuits screws I8 as shown in Fig. 1. At each side of it is desirable to provide for the simultaneous .the upper half of the ring I6 there is provided a control of a plurality of adjustable resistors or recess I9 for receiving the head of the cap screw potentiometers. These potentiometers which are 10 I8. The recess is is joined by a bore 2| for reprovided with a unitary control are of the preciceiving the body of the cap screw l8. Each of 1 $1011 yp having an accuracy Within one P rce t the lower ring portions I1 is provided with a of the total resistance val e. In ali n such capped bore 22 for receiving the threaded portion resistors or potentiometers it has been found in of the cap screw I8. the past that it was rather diflicult to provide for From Figs. 3 and 4 it will be noted that the adjustment or synchronization of the diflerent inner surface of each of the rings I5 has a chamresistor or potentiometer units relative to each fered edge 23 and the inner surface of each ring other and relative to the unitary control shaft. is slightly concave as is indicated by the surface It is, therefore, an object'of the present inven- 24 in Fig. 4 and Fig. 5. The slightly conc tion to provide an improved arrangement whereface 24 engages the inclined surfaces III and 20 by the adjustment or synchronization of a p1u formed adjacent the grooves I3 and I4 so as to rality of Precision ype variable resistors .or tend to draw together opposite surfaces of adjapotentlometels ay be obtained in a relatively cent casings ll of the potentiometer. This action simple manner. also aligns the openings in the movable contact Still another object of the present invention 25 arms of the potentiometers with such precision is to Provide an improved c p d a tenin that a unitary control shaft 9 readily passes device for retaini to e in anged relation through all of the movable contact arms, and the a plurality of potentiometers or adjustable revarious potentiometers II without binding. sistors. By means of measuring instruments the posi- Other and further objects of the present inventions of the resistance units in their various cast o ub q y will become apparent by refe ings Il may be adjusted relative to each other so ence to the following description taken in conas to provide the desired synchronization or adlunction with the accompanying -.-drawines justment of one resistor relative to the other. wherein: This is accomplished by loosening slightly the Fig. 1 shows the application of the p se t clamping rings I5 until the desired adjustment vention to a gangedpotentiometer unit; has been obtained by grasping one casing with Fig. 2 is a plan view of a clamping ring emone hand and moving the adjacent casing with ployed in the ganged unit of Fig. 1; the other hand. Thereupon, the clamping ring Fig. 3 is a side view of a clamping ring shown between these two casings may be tightened. A in Fig. 2; 40 similar procedure is followed for successive pairs Fig. 4 is a cross-sectional view of the ring of of casings. By this arrangement the desired 2 as See in t d ct o e a ws a o accuracy in the control may be obtained.- the line 4-4; and While for the purpose of illustrating and de- Fi 5 is an enlarged V of a portion of Fig. 1. scribing the present invention a preferred em- A a ed potentiometer u is shown in 1 bodiment has been shown in the drawings, it is as having a u t r control shaft 9 which extends to be understood that the invention is not to be into a plurality of Potentiometers each having limited thereby since such variations in the conan outer casin lac of e casings is P struction are contemplated as may be commenvided with an electrica te ina assembly l2 surate with the spirit and scope of the invention whereby circuit connections may be made to the as defined in the accompanying claims. resistor and the adjustable contact of the po- What I desire to protect by United States Lettentiometer. Each Of the casings H is provided ters Patent is claimed as follows; at its front side with a groove I3 having an in- 1. The combination for adjusting a ganged clined surface Ill; at its b side it is Provided assembly of precision variable resistors compriswith a groove I4 having an inclined surface III. II in; a plurality of cylindrical casings eachpro- 3 vided adjacent their front and rear-sides with an annular ridge, a rigid clamping ring having a channel-like cross-section whereby the edges of the channel sides engage adjacent ridges of adjacent casings thereby to produce a force transverse to said ring to move together adjacent front and rear sides of the assembled casings, said clamping ring being formed in two parts, and means for tightening together said two parts of said clamping ring.

2. The combination for adjusting one resistor angularly relative to another resistor in a ganged assembly of precision variable resistors comprising a plurality of cylindrical casings-each provided adjacent their front and rear sides with an annular ridge, a rigid two-part clamping ring having parallel edge surfaca for chi -B g adjacent ridges of adjacent casings without substantial engagement of the remainder of the casings, the contacting surfaces of said ring and said ridges having surfaces at angles to each other thereby to tend to force together adjacent front and rear sides of the assembled casings as said ring is tightened, symmetrically positioned means for tightening the parts of said clamping ring, and a common control shaft for said assembly.

3. The combination comprising a gang of precision potentiometers each having a cylindrical casing, an annular groove located adjacent the front side of said casing, a similar groove located adjacent the back side of said casing, said grooves each forming adjacent the sides of said casing a narrow ridge having a surface inclined toward the body of said casing, a rigid two part clamping ring located about said ridges where adjacent potentlometers meet, said ring having a recessed inner surface with the inner peripheral edges thereof engaging said inclined surfaces and extending partially into said grooves,

and means for tightening the parts of each ringtogether.

4. The combination for adjlltably sansins together a plurality of precision variable rdstors to permit relative rotation therebetween oomprisingacylindricaicasingforeaehm, saidcasinghavinganannulargroovelocatedadjacent each of the front and back sides thereof toformnarrowridges,arigidclampingring formed in two similar parts having a concave inner surface for engaging only the rear and front ridges of adjacent casings. the inner edges of each ring extending partially into said grows soastobeoutofcontactwiththeremainderoi said casing, a plurality of screws for tightening each ring, and a common control shaft for said resistors.

5. The combination for adjustably ganging together a plurality of precision variable resistors in adjusted angular relation to each other comprising a cylindrical casing for each resistor. each casing having an annular ridge located adjacent each of the front and back sides thereof, each ridge having one inclined wall on the side toward the body of the casing, a rigid clamping ring formed in two similar parts each having a recessed inner surface whereby the parallel edges of each ring engage only the inclined sides of the front and rear ridges of adjacent casings, a plurality of screws for tightening each ring to lock in position adjacent resistors and to align the bearings thereof, and a common control shaft passing through the bearings of said resistors.

RAYMOND W. SIARLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,928,206 e Sept. 12, 1933 2,214,381 Rastetter Sept. 10, 1040 

